1. Field of the Invention
The present invention relates to a tampon applicator to be employed when a sanitary tampon is to be inserted into a human body.
2. Description of the Related Art
The applicator for the sanitary tampon is constructed to include an outer cylinder for fitting the tampon therein, and an inner cylinder inserted into the outer cylinder and protruding rearwardly from the root end of the outer cylinder. A take-out cord, as extended from the tampon, is led out of the outer cylinder through the inner cylinder and protruded rearwardly from a rear end of the inner cylinder.
When the tampon is to be employed, the outer cylinder is inserted into a vaginal cavity, and the inner cylinder is pushed to push the tampon out of the outer cylinder. Then, the tampon is inserted into the vaginal cavity while expanding a number of deformable valves at the leading end of the outer cylinder.
Some of the existing applicators are formed to have an outer cylinder and an inner cylinder which are made of paper. In recent years, however, an outer cylinder injection-molded of a synthetic resin has been employed so that it may have a smooth surface and may be smoothly inserted into the vaginal cavity. In this case, the inner cylinder is also generally formed by the injection-molding method.
However, the inner cylinder of the applicator takes a high molding cost if it is injection-molded of a synthetic resin, because the mold to be employed for the injection molding is expensive. When the diameter of the inner cylinder or the diameter of the push portion at the leading portion of the inner cylinder has to be changed for changing the shape of the product, on the other hand, the mold has to be remade to increase the cost for this design change.
On the other hand, since the tampon applicator is dumped after use, it is preferable for the environment to minimize the amount of resin to be employed. Accordingly, by making at least the inner cylinder thin and diametrically small, it is possible to reduce the amount of resin to be employed. However, the injection-molding method cannot realize the thin, diametrically small inner cylinder, because of the following reasons:
(1) Upon forming the inner cylinder by the injection-molding method, a plurality of the inner cylinders are simultaneously injection-molded at one shot of a molten resin. Accordingly, in order to stabilize the quality of the molded inner cylinders while keeping the satisfactory fluidicity of the resin in the mold, the thickness of the inner cylinders have to be enlarged to a considerable extent, so that it is essentially impossible to injection-mold the inner cylinders having a thickness of 0.6 mm or less. On the other hand, if the external diameter of the inner cylinder is reduced, the passage for the cooling water cannot be formed in the cored mold (or insert die) which is located on the inner side of the inner cylinder upon injection-molding. As a result, it takes a long time to cool the mold, so that the cycle time for the injection-molding is expanded to degrade the molding efficiency.
(2) On the other hand, in case of the injection-molding, it is difficult to orient the resin in the axial direction of the inner cylinder, so that the molded inner cylinder cannot be strengthened in the axial direction thereof. Accordingly, if the inner cylinder is made thin and diametrically small, the inner cylinder is easily buckled and deformed in the axial direction when it is put out of the mold after injection-molding. On the other hand, if the inner cylinder has a low axial strength, there is a possibility of being buckled and folded when the inner cylinder pushes out the tampon to be employed.
The invention has an object to provide a tampon applicator which can manufacture the inner cylinder at low cost, can enhance the buckling strength in the axial direction even when the inner cylinder is made thin and diametrically small, and can easily deform the shape of the inner cylinder according to the change in the shape of the outer cylinder.
According to an aspect of the invention, an applicator for a tampon may comprise: an outer cylinder including a protruding mouth at a leading end thereof, through which a tampon is pushed out and an opening at a root end thereof; and an inner cylinder for pushing out the tampon which has a front end located in the outer cylinder and a rear end protruding rearwardly from the outer cylinder through the opening,
wherein the inner cylinder is formed of an extruded material which is extrusion-molded of a thermoplastic resin into a cylindrical shape, and is provided at the front end thereof with a push portion which is deformed to have a larger diameter from the extruded material.
For example, the outer cylinder includes a large diameter portion for fitting the tampon therein, and a small diameter portion extending from the large diameter portion toward the root end, and
wherein the push portion of the inner cylinder is positioned in the large diameter portion and has a larger external diameter than an internal diameter of the small diameter portion.
According to the invention, the inner cylinder of the applicator is made of the excluded material of the thermoplastic resin so that the cost for manufacturing the inner cylinder can be lowered. On the other hand, the extruded material can freely select the thickness and the external diameter in comparison with the injection-molding, so that the thin, diametrically small inner cylinder can be formed with a smaller amount of employed resin. Furthermore, the inner cylinder made of the extruded material of the thermoplastic resin can be easily formed with the diverging push portion at the front end which is located within the outer cylinder.
On the other hand, it is preferable that the extruded material is extrusion-molded and then axially oriented.
Since the resin is oriented in the axial direction of the inner cylinder, the axial strength of the inner cylinder can be enhanced, and the buckling strength thereof can also be enhanced even if it is made thin and diametrically small. Accordingly, in process of manufacturing or at the time of using the inner cylinder, it can prevent the inner cylinder from being folded due to the buckling.
Moreover, it is preferable that an external diameter of the push portion is gradually diverged toward the front end.
With this shape, the push portion can be simply shaped merely by heating and pushing a press die having a tapered portion, for example, onto the front end of the inner cylinder.
Moreover, the inner cylinder can also be provided at the rear end with a diverging portion which is deformed to have a diameter gradually enlarged toward the rear end.
In this case, it is preferable that the diverging portion formed at the rear end of said inner cylinder have an edge portion which is bent outwardly or inwardly of the diverging portion.
When the applicator is to be used, the user pushes the rear end of the inner cylinder with the finger. If the edge portion of the diverging portion is bent, the edge portion of the inner cylinder will not contact with the finger to reduce the resistance to the finger. Accordingly, the tampon can be easily inserted into the vaginal cavity.
Moreover, it is preferable that the push portion formed at the front end of the inner cylinder have an edge portion which is bent outwardly or inwardly of the push portion.
When the applicator is employed to insert the tampon into the vaginal cavity, the edge portion of the push portion at the front end of the inner cylinder may contact with a portion of the user""s body. In this case, the uncomfortable feeling, as might otherwise be caused by the contact with a portion of the body, is eliminated if the edge portion is bent.
In this case, it is preferable that a bent portion which is bent outwardly or inwardly of the push portion has a width size smaller than a thickness of a take-out cord extending from said tampon.
In manufacturing process, the take-out cord of the tampon is inserted from the outer cylinder into the inner cylinder. At this time, the width size of the bent portion at the front end of the inner cylinder is made smaller than the thickness of the cord, so that it prevents the take-out cord from being caught in the clearance between the bent portion and the inner wall of the outer cylinder. As a result, it becomes easy to insert the tampon into the applicator.